<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    // let i = 1
    // while (i <= 100) {
    //   document.write(`${i}<br>`)
    //   i++
    // }
    // 1-100总和并输出
    // let i = 1
    // let sum = 0
    // while (i <= 100) {
    //   sum += i
    //   i++
    // }
    // document.write(sum)
    //1-100之间所有偶数和
    let i = 1
    let sum = 0
    while (i <= 100) {
      if (i % 2 === 0) {
        sum += i
      }
      i++

    }
    document.write(sum)


  </script>
</body>

</html>